Add Linker and Optimizer modules with API integration and frontend components

- Added Linker and Optimizer apps to `INSTALLED_APPS` in `settings.py`.
- Configured API endpoints for Linker and Optimizer in `urls.py`.
- Implemented `OptimizeContentFunction` for content optimization in the AI module.
- Created prompts for content optimization and site structure generation.
- Updated `OptimizerService` to utilize the new AI function for content optimization.
- Developed frontend components including dashboards and content lists for Linker and Optimizer.
- Integrated new routes and sidebar navigation for Linker and Optimizer in the frontend.
- Enhanced content management with source and sync status filters in the Writer module.
- Comprehensive test coverage added for new features and components.

backend/igny8_core/modules/linker/serializers.py

@@ -0,0 +1,42 @@
+from rest_framework import serializers
+from igny8_core.business.content.models import Content
+
+
+class LinkContentSerializer(serializers.Serializer):
+    """Serializer for linking content"""
+    content_id = serializers.IntegerField(required=True)
+    
+    def validate_content_id(self, value):
+        try:
+            content = Content.objects.get(id=value)
+            account = self.context['request'].user.account if hasattr(self.context['request'].user, 'account') else None
+            if account and content.account != account:
+                raise serializers.ValidationError("Content not found or access denied")
+            return value
+        except Content.DoesNotExist:
+            raise serializers.ValidationError("Content not found")
+
+
+class BatchLinkContentSerializer(serializers.Serializer):
+    """Serializer for batch linking"""
+    content_ids = serializers.ListField(
+        child=serializers.IntegerField(),
+        min_length=1,
+        max_length=50
+    )
+    
+    def validate_content_ids(self, value):
+        account = self.context['request'].user.account if hasattr(self.context['request'].user, 'account') else None
+        if not account:
+            raise serializers.ValidationError("Account not found")
+        
+        content_ids = Content.objects.filter(
+            id__in=value,
+            account=account
+        ).values_list('id', flat=True)
+        
+        if len(content_ids) != len(value):
+            raise serializers.ValidationError("Some content IDs are invalid or inaccessible")
+        
+        return list(content_ids)
+